From Python and learning Ruby coding assistance

I've been learning Python for the last 6 months and have done over a 100 problem exercises and I am now tryinglearn Ruby and solve these exercises in Ruby. This is the exercise I'm having issues with, as I feel as if I'm over complicating things and yet not doing it the right way. This is the exercise:

A robot is moving on a grid and has starting position (0,0). The robot can be directed to move a given number of steps up, down, left, or right.
Write a function that takes in a list of instructions and outputs the distance (in a straight line) the robot is from its starting position. The distance should be rounded to the nearest integer.
The instructions are given as a single array of directions followed by a number of steps to be taken in that direction.